Affiliation:
1. Department of Electronics and Computer Science, National Institute of Technology , Nagano College, 716 Tokuma, Nagano 381–8550
Abstract
Abstract
We show that variations in the energy of a cyclotron resonant scattering feature with luminosity can be explained by considering a variation of the bulk velocity of infalling matter in the two-dimensional structure of an accretion column. Variations in the energy of a cyclotron line with luminosity are computed by taking into account the variation in gradient of the bulk velocity with luminosity in a line-forming region. We mainly discuss the positive correlation between the energy of the cyclotron line $E_{cyc}$ at the fundamental and the luminosity as observed in the spectra of GX 304−1, A0535+262, and Vela X-1, considering a change in gradient of the bulk velocity in the line-forming region with luminosity in addition to a change of altitude of the line-forming region with luminosity. Consequently, we demonstrate that the change in the observed line energy with luminosity can be successfully reproduced by a variation in bulk velocity due to radiation pressure as well as the altitude of an accretion mound.
Publisher
Oxford University Press (OUP)
Subject
Space and Planetary Science,Astronomy and Astrophysics
Cited by
1 articles.
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